During the late nineteenth and early twentieth centuries, millions of immigrants migrated to the United States of America, hoping to live the American Dream. Before the American Civil War, most immigrants arrived in the United States from Great Britain, Germany, and Ireland. By the 1880s, the home countries of immigrants began to change. Many of the new immigrants to arrive in the United States came from Eastern and Southern European countries, like Romania, Montenegro, Albania, Poland, Hungary, Lithuania, and Czechoslovakia, rather than from Western European countries, like Great Britain, Ireland, and Germany.

In 1860, 328,249 immigrants lived in Ohio. These people accounted for fourteen percent of the state's population. By 1900, the number of immigrants in Ohio rose to 458,734, but the percentage of the population that was foreign-born declined to eleven percent. Most of these immigrants in 1900 came from Germany, Great Britain, and Ireland, yet a growing number of Eastern and Southern Europeans were also migrating to the state.

In 1914, nearly twenty thousand Romanian immigrants resided in Ohio. Most of these Romanians settled along Lake Erie, especially in Cleveland, where they found low-paying jobs in factories or worked as day laborers. Most Romanian immigrants came to the United States to improve their financial situation, to escape political turmoil in their native country, or to escape from Austria-Hungary, which controlled several sections of Romania at this time. Most of these immigrants were illiterate and, thus, were forced to accept low-paying positions. Immigrants who were more successful established businesses that supplied their fellow migrants with traditional Romanian products. To help maintain their traditional culture, Cleveland's Romanians eventually established their own newspapers, the Romanul, the Solia, the America, the Foia Poporului, and the Unirea. In 1904, they also established St. Mary's, the first Romanian Orthodox church in the United States. Romanian migrants also formed the Carpatina Society, a social and mutual-benefit society. In Cleveland and other communities, the Romanian immigrants tended to settle in their own communities, preferring to live among people who shared similar cultural beliefs and spoke the same language as they did.

Romanian immigrants congregated together partly out of camaraderie but also out of fear. During the late nineteenth and early twentieth centuries, many native-born Americans feared outsiders. Some of these people objected to the immigrants' religious and cultural beliefs, while others believed that the foreigners would corrupt the morals of United States citizens. These people also contended that the quality of life within the United States would decline, as there were not enough jobs to employ the millions of people migrating to America. Many native-born Americans hoped either to limit immigration or to force foreigners to convert to American customs and beliefs. The leaders of this movement were the Progressives of the late 1800s and the early 1900s. To accomplish their goals, the Progressives implemented numerous reforms, including settlement houses, which taught foreigners American practices. The Progressives also called for laws that would either limit or ban the cultural practices of recently arrived immigrants. It would take several generations before the immigrants became truly accepted by the vast majority of white Ohioans.

While many Romanian immigrants arrived in the United States prior to World War I, following this conflict, a sizable number of Romanian Americans left the United States. Following World War I, Romania gained significant territory from Austria-Hungary, and many Romanians returned to their homeland. Of Cleveland's twelve thousand Romanians, six thousand returned to their native country. New immigration from Romania to the United States ended until after World War II, which destroyed numerous homes and businesses in Romania. At this time, many residents of this country sought a better life in the United States. Ohio's Romanian residents actively assisted these new arrivals in beginning new lives. The new immigrants tended to settle in the already established Romanian communities in the state. In the late 1940s and the early 1950s, approximately two thousand Romanian migrants settled in Cleveland.

Over the succeeding decades, Ohio's traditional Romanian communities began to lose their cohesiveness. As other Ohioans became more tolerant of the Romanians, many Romanian communities began to disintegrate. Many Romanians moved into other communities, while non-Romanians began to infiltrate the traditionally Romanian neighborhoods. Romanian Ohioans continue to participate in various social and cultural groups that serve to promote Romanian beliefs and customs. Cleveland continues to be the home city for the Union & League of Romanian Societies, the largest mutual-benefit society, serving Romanian descendents in the United States and Canada.